基于MIDAS深基坑开挖对近距离高架桥的安全影响研究

Safety impact of deep foundation pit excavation for close distance viaduct using MIDAS

以长沙市地铁5号线三一大道车站深基坑工程为对象,利用MIDAS/GTS/NX软件模拟基坑开挖对近接构筑物影响,重点研究高架桥桥墩沉降和桩基变形随深基坑地下水位改变,不同施工过程及支护形式等多因素的变化规律。通过与现场监测数据对比分析表明:在富水复杂地质和周边环境下,长沙地铁深基坑施工所采用的围护结构安全合理;旋喷桩,地下连续墙和支撑组合能有效控制基坑施工过程中引起的近距离高架桥变形。同时验证了MIDAS/GTS/NX能很好地模拟基坑开挖,指导实际工程。

As an example of deep foundation pit project of Sanyi Avenue station of Changsha Metro Line 5, excavation on adjacent structures of foundation pit is simulated using MIDAS/GTS/NX software, and it is studied that viaduct pier settlement and deformation of pile foundation is changed with the variation of groundwater level of deep foundation pit, also the change rule of different factors in construction process and support form. Through the analysis and comparison, the field monitoring data show that in the water rich in complex geological and surrounding environment, retaining structure of deep foundation pit construction safety Changsha subway is reasonable; jet grouting pile, underground continuous wall and supporting the combination can lead to effective control during the construction of foundation pit. It is confirmed that MIDAS/GTS/NX can well simulate the excavation of the foundation pit and guide the practical engineering.